As dampers for speedily damping vibrations such as lateral shaking occurring in a structure due to an earthquake or the like, those using the viscous deformation of a viscous material, those using the plastic deformation of lead, steel rods, or the like, and those using the friction of a sliding member, among others, are known.
In the damper using a viscous material, much time is required in the charging operation of the viscous material, and it is necessary to provide a tight seal for preventing the leakage. In the damper using lead, a steel rods, or the like, there is a risk of environmental contamination due to lead, and it is required to firmly hold both ends of lead, the steel rod, or the like, respectively, to a pair of members which are displaced relative to each other.
Meanwhile, In the damper using a sliding member, there is a possibility of deterioration in characteristics due to the wear of the sliding member. Further, a sliding layer of the sliding member can peel off, which can also possibly cause deterioration in characteristics.
The present invention has been devised in view of the above-described aspects, and its object is to provide a friction damper which has a simple structure, is capable of reducing wear and the exfoliation of the sliding layer as practically as possible, and makes it possible to obtain stable damping characteristics over a long period of time.